Noise-Induced Hearing Loss

It is estimated that the UK economy loses around £25 billion every year in productivity and unemployment through hearing loss (International Longevity Centre 2014). A substantial element of this could be eliminated by applying often simple measures to protect hearing.

• WHO forecast over 1 billion young adults at risk of permanent, avoidable hearing loss due to unsafe listening practices by 2030.
• By 2050 nearly 2.5 billion people projected to have some degree of hearing loss and at least 700 million will require hearing rehabilitation.
• WHO analysis shows that 16 per cent of hearing loss worldwide is caused by exposure to excessive noise in the workplace (WHO, 2002).
• An estimated 30 per cent of people of working age with severe hearing loss are unemployed (UK, Action on Hearing Loss 2013).
• Worker’s hearing may be further impacted by the significant increase in exposure levels from personal entertainment.

Even though the number of people exposed to high noise levels through traditional trades such as mining, and heavy industrial work has decreased; the number of people exposed to excessive sound through leisure activities such as using personal music players, gaming, attending gigs and nightclubs, has trebled since the 1980s. We are unsure of the scale of this problem, but early evidence suggests that many young people are already entering the workforce with hearing damage.

The UKHCA would obviously want to shift people away from reliance on hearing protection and move towards more rigorous application of the hierarchy of control. However, we recognise that there is a need to educate those specifying, procuring, and using these HPDs to ensure that where they are needed, they can be used properly, safely and with confidence that they do their job. One question the UKHCA will be exploring on an international platform is the use of ear fit testing as a tool to engage and educate in this area.

More than just hearing loss

Most people recognise the direct effects noise can have on the auditory system resulting in noise induced hearing loss, tinnitus (noises or ringing in the ears), or hyperacusis (sensitivity to loud noise). Even though these risks are often understood the debilitating, disabling and isolating results of these permanent effects are greatly underestimated.

Many chemicals used in the workplace and drugs such as some antibiotics or chemotherapy treatments also have an ototoxic effect on our hearing system and can also result in permanent hearing loss and tinnitus.

Less well appreciated are the other known implications for health related to noise exposure, resulting in cognitive decline, coronary and circulatory problems and depression or stress.

Recent research has established a link between hearing loss and dementia finding that adults with hearing loss are significantly more likely to develop dementia over time than those who retain their hearing. Hearing loss is in fact considered the largest controllable factor in the risk for developing dementia.

Exposure to excessive noise can also result in an increased chance of being involved in accidents due to distraction and loss of audibility.

Are all ear canals equal?

Hearing Protection Devices (HPDs) are a common solution to noise exposure in the workplace. They are often relied upon to prevent exposures to noise levels which can cause irreversible hearing health harm.

The amended Personal Protective Equipment (EC Directive) Regulations 1992 which came into force on 21 April 2018 now identifies workplace noise as a significant health risk. Hearing protection was previously defined as category II, along with high-visibility clothing, safety eyewear and head protection. In the most recent revision to the regulations HPDs are now in category III, alongside PPE that protect against the most serious of risks such as falls from height, chainsaw cuts and contact with substances hazardous to health including respiratory protective equipment (RPE).

“recent research has found that adults with hearing loss are significantly more likely to develop dementia”

Those of us involved in promoting a higher profile for hearing conservation and calling for better standards of intervention of course welcomed this increased level of recognition for the seriousness of the health impact from noise. However, has it stimulated any change in our attitude to noise?

In many work and leisure scenarios hearing protection devices (HPDs) such as ear plugs or earmuffs, are the only solution provided for individuals to be able to reduce noise exposure and protect their hearing and general health. However, we know from HSE research that commonly used earplugs are generally poorly fitted and that an incorrectly fitted device may give virtually no protection (HSE Research Report 720). The following image shows that removing hearing protection for even a short time in a noisy environment result in a rapid drop off of attenuation provided.

Conversely many employers go for the highest protection device or mandate blanket HPD wearing on sites and premises. Here the issue of over protection can put workers at risk of serious accidents, injury and death.

So, if your hearing conservation programme relies on the performance of HPDs can you really be sure they are doing the job expected of them?

If we apply the same standards and principles expected for reliance on respiratory protective devices (HSG 53); the guidance talks in detail about selection that is both adequate and suitable for the hazard, environment and specifically the user.

The guidance for respiratory protection (HSG 53) provides detailed advice on these matters and also requirements for fit testing of every type of RPE that will be worn by each individual. The rationale for requiring fit testing for RPE includes the following facts:

• Faces can vary widely in shape, size and proportion, so selecting the correct model is vital for safe fit.
• Protection relies on achieving a good seal between the facepiece and the wearer’s face.
• Fit testing must happen during the initial selection of PPE, before the mask is worn in a hazardous environment.

Let’s relate this to ears and HPDs:

• Ear canals can vary widely in shape, size and proportion, so selecting the correct model is vital for safe fit.
• Protection relies on achieving a good seal between the HPD and the individuals ear canal.
• Fit testing must happen during the initial selection of PPE, before the HPD is worn in a hazardous environment.

When selected as a control measure, hearing protector performance is critical to help ensure individual protection where it is relied on within the context of hearing conservation programmes. There has been an emergence of commercially available systems that offer the capability of individually fit testing hearing protectors to assess how much attenuation an individual user is receiving based on the type of hearing protector, fitting technique and worker motivation. Hearing protection fit test systems either calculate a Personal Attenuation Rating (PAR) which is an estimation of the noise reduction obtained across test frequencies in one or both ears expressed as a single number or show a simple pass/fail without full attenuation characteristics. The time involved in conducting a fit test session with different systems ranges from a few minutes to up to 20 minutes, depending on the test method employed.

Individual fit testing plays an important part in helping to educate workers and address issues of comfort, fit and achieving appropriate protection from hearing protection. Fit testing highlights the importance of actual protection achieved by a hearing protection device fitted by the user in the workplace setting and helps identify training needs.

You can’t argue with that can you?

Given the reliance on HPDs as a commonly applied final level of protection against harmful noise, the challenges related to reliance on laboratory-based attenuation values, alongside individual behaviours in use and fit; the UKHCA supports the concept of individual fit-testing as a useful assurance methodology that could be added to an employer’s hearing conservation programme. This would provide both the user and the employer an opportunity to ensure protection being provided is as expected and the chance to coach and adapt support as necessary.

International standards are beginning to recognise the need for an agreed approach to ensuring quality and consistency in HPD fit testing and the relevant EN standard is already required to be met for all custom-made HPDs. Amendments to Annex II of the PPE Directive are also looking likely to include requirements for fit testing assurance in the future.

From a hearing conservation perspective putting guidance to the Control of Noise at Work Regulations, alongside EN Standards being available for HPD fit testing devices, we would hope will improve the selection, use and subsequently protection provided by HPDs in practice. I would also like to think that having such guidance and standards will highlight not only the need for good fit for these devices but elevate the understanding and acceptance of noise as a serious health risk and place increased focus on the hierarchy of control for improved management of noise exposure for our workers.

“fit testing can be integrated into an ongoing health surveillance programme”

Benefits of a fit testing programme

Fit testing can benefit a hearing conservation approach in a number of ways:

1. Improving the likelihood that a hearing protection device can actually protect the wearer and is appropriate for their needs.
2. Providing insights and allowing a more targeted approach to training and information provision on how to select, use and care for hearing protection devices. Fit testing can be integrated into an ongoing training or health surveillance programme.
3. Can provide useful documentation and record keeping regarding hearing protector suitability and adequacy.
4. Can be used as a tool to assess the overall effectiveness of an employer’s hearing conservation programme and to direct corrective actions where needed.
5. Can enable the hearing conservation professional to match the employee’s hearing protector attenuation to his/her noise exposure level. This may be particularly useful in hearing-critical jobs or for those with hearing impairment.
6. Can aid in the selection of appropriate hearing protection for staff, where a variety of protectors can be tested, and the most effective model selected for that individual.

The UKHCA has produced a guidance document which aims to help companies and individuals interested in fit testing for hearing protection to understand the benefits it can bring in assuring workers health and safety. It details the methods available and the importance of selecting both adequate and suitable devices. The document can be downloaded here: https://hearingconservation.org.uk/ukhca-hearing-protection-fit-testing-an-introductory-guide/

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Acknowledgements

This document has been produced by the UK Hearing Conservation Association as an information document for those wishing to understand the value and options when considering fit testing as part of a hearing conservation programme.

References

EN 17479:2021- Guidance on selection of individual fit testing methods describes the different types of fit testing available at the time of publication. (Available for purchase from BSI).

HSE, 2009 Real world use and performance of hearing protection. Research Report 720.

Additional resources

Berger, E.H (2007). “Fit testing hearing protectors,” CAOHC Update 19(2), 5-8. 2.

Hager, L. D. (2007). “Hearing Protector Evaluation: Current Standards and Pending Developments,” Hearing Rev. 14(3), 26-28. 3.

Hager, L. D. (2006). “Fit Testing Ear Plugs,” Occupational Health and Safety75(6), pages 38-42 and 135. 4.

Berger, E.H. (1989). “Exploring Procedures for Field Testing the Fit of Earplugs,” Proceedings, 1989, Industrial Hearing Conservation Conference, University of Kentucky, Lexington, KY, 7-10. 5.

Witt, B. (2007). “Putting the Personal Back into PPE: Hearing Protector Effectiveness.” Occupational Health and Safety 76(6), 90-94 6.

Witt, B (2007).”Fit Testing of Hearing Protectors.” Occupational Health and Safety 76(10), 118-122.